A 500kV single-phase autotransformer replacement operation evaluation method and system

Abstract

The present invention provides a 500kV single-phase autotransformer replacement operation evaluation method and system, which comprehensively considers the transformer equivalent mathematical model under the combined effects of factors such as short-circuit voltage percentage, transformer capacity, winding equivalent capacitance, voltage taps, etc. before and after transformer replacement, thereby simplifying the parameter input of modeling analysis and improving the efficiency of modeling simulation; on this basis, a comprehensive evaluation is carried out with three-phase voltage unbalance, zero-sequence current, interphase circulating current, operation thermal stability, etc. as indicators, and a universal 500kV single-phase autotransformer replacement operation evaluation method and measures for optimizing operation capacity are proposed.

Description

Technical Field

[0001] The present invention relates to the technical field of single-phase autotransformers, and in particular to a 500kV single-phase autotransformer replacement operation evaluation method and system. Background Art

[0002] In terms of transformer fault replacement operation: There are relevant literatures that can carry out comprehensive evaluation of fault replacement of power plant transformers, mainly including comprehensive factors of feasibility of transformer parallel operation, on-site installation, etc. There are few research literatures on fault replacement analysis of 500kV single-phase autotransformers. At present, there are only a few evaluations carried out on actual engineering problems. The evaluation is carried out through simulation analysis of PSCAD electromagnetic transient model established based on actual engineering parameters. The evaluation content only considers a single influencing factor that appears in the actual engineering.

[0003] The main transformer of the power plant is mainly a double-winding three-phase transformer. The three-phase parameters of the transformer itself are symmetrical, which is fundamentally different from the fault replacement of the single-phase autotransformer used in the 500kV substation, and the evaluation method cannot be directly applied; there is an interactive relationship between the influencing factors before and after the replacement of the 500kV single-phase autotransformer, which cannot be simply superimposed. Therefore, the existing evaluation and analysis methods for actual engineering problems are not universal; there is currently no comprehensive evaluation method for the fault replacement operation of 500kV single-phase autotransformer that takes into account the combined effect of comprehensive factors. Summary of the invention

[0004] In order to solve the above problems in the prior art, the present invention provides a 500kV single-phase autotransformer replacement operation evaluation method and system, which comprehensively considers the transformer equivalent mathematical model under the combined effects of factors such as short-circuit voltage percentage, transformer capacity, winding equivalent capacitance, voltage tap, etc. before and after transformer replacement, thereby simplifying the parameter input of modeling analysis and improving the efficiency of modeling simulation; on this basis, a comprehensive evaluation is carried out with three-phase voltage unbalance, zero-sequence current, interphase circulating current, operation thermal stability, etc. as indicators, and a universal 500kV single-phase autotransformer replacement operation evaluation method and measures to optimize operation capacity are proposed.

[0005] A first aspect of the present invention provides a 500kV single-phase autotransformer replacement operation evaluation method, comprising:

[0006] Obtaining nameplate parameters of a healthy phase transformer and nameplate parameters of a replacement phase transformer, and respectively calculating equivalent parameters of the healthy phase transformer and equivalent parameters of the replacement phase transformer according to the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer;

[0007] Obtain system equivalent parameters and load parameters under peak load conditions, valley load conditions, and daily operation load conditions of the target substation;

[0008] A simulation model is established according to the operation mode of the target substation, and the calculated equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer are input into the simulation model, and the medium voltage side gear voltage of the replacement phase transformer ratio parameter is adjusted to be consistent with the medium voltage side gear voltage of the healthy phase transformer ratio parameter. If there is no consistent gear, the voltage is taken to be the gear closest to the gear;

[0009] Inputting system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation into the simulation model;

[0010] Performing simulation analysis on the simulation model to obtain operation data of peak load conditions, operation data of valley load conditions, and operation data of daily operation load conditions;

[0011] Calculate steady-state characteristic index and transient characteristic index according to the operation data of the peak load condition, the operation data of the valley load condition, and the operation data of the daily operation load condition;

[0012] Determine whether the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of replacing the transformer operation;

[0013] If both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation, then it is feasible from the operation technology point of view, and the replacement operation can be implemented after the economic feasibility and engineering installation feasibility are evaluated by the operation department;

[0014] If at least one of the steady-state characteristic index and the transient characteristic index does not satisfy the condition for the feasibility of the replacement transformer operation, the load of the replacement transformer is reduced until both the steady-state characteristic index and the transient characteristic index satisfy the condition for the feasibility of the replacement transformer operation.

[0015] Furthermore, if at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of operation of the replacement transformer, and if reducing the load of the replacement transformer still cannot make both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of operation after replacing the transformer, the operation mode of the medium-voltage side bus is adjusted for optimization, and the simulation model is simulated and analyzed again after optimization.

[0016] Further, the equivalent parameters of the healthy phase transformer include: the equivalent resistance per unit value of the healthy phase transformer, the equivalent reactance per unit value of the healthy phase transformer, the equivalent conductance per unit value of the healthy phase transformer, and the equivalent susceptance per unit value of the healthy phase transformer;

[0017] The equivalent parameters of the replacement phase transformer include: the equivalent resistance per unit value of the replacement phase transformer, the equivalent reactance per unit value of the replacement phase transformer, the equivalent conductance per unit value of the replacement phase transformer, and the equivalent susceptance per unit value of the replacement phase transformer.

[0018] Furthermore, the steady-state characteristic indicators include: transmission power on three sides of the main transformer, three-phase current imbalance, three-phase voltage imbalance, zero-sequence current, zero-sequence voltage and parallel operation capability of the main transformer;

[0019] The transient characteristic indicators include: maximum short-circuit current and magnetizing inrush current of the no-load transformer when the switch is closed.

[0020] Furthermore, if at least one of the steady-state characteristic index and the transient characteristic index does not satisfy the condition of the feasibility of the replacement transformer operation, the method further includes:

[0021] The load capacity of the replaced main transformer is checked to obtain the boundary load rate of the replaced three-phase main transformer.

[0022] A second aspect of the present invention provides a 500kV single-phase autotransformer replacement operation evaluation system, comprising:

[0023] A data acquisition calculation module is used to obtain the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer, and calculate the equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer according to the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer; the data acquisition calculation module is also used to obtain the system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation;

[0024] A simulation module is used to establish a simulation model according to the operation mode of the target substation, input the calculated equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer into the simulation model, and adjust the medium voltage side gear voltage of the replacement phase transformer ratio parameter to be consistent with the medium voltage side gear voltage of the healthy phase transformer ratio parameter. If there is no consistent gear, the voltage is taken to be the gear closest to the gear; the simulation module is also used to input the system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation into the simulation model;

[0025] A working condition data calculation module is used to perform simulation analysis on the simulation model to obtain operating data of peak load working conditions, operating data of valley load working conditions, and operating data of daily operating load working conditions;

[0026] A characteristic index calculation module, used to calculate a steady-state characteristic index and a transient characteristic index according to the operation data of the peak load condition, the operation data of the valley load condition, and the operation data of the daily operation load condition;

[0027] The judgment module is used to judge whether the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation; if the steady-state characteristic index and the transient characteristic index both meet the conditions for the feasibility of the replacement transformer operation, it is feasible from the operation technical point of view, and the replacement operation can be implemented after the economic feasibility and engineering installation feasibility are evaluated by the operation department; if at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of the replacement transformer operation, the load of the replacement transformer is reduced until the steady-state characteristic index and the transient characteristic index both meet the conditions for the feasibility of the replacement transformer operation.

[0028] Furthermore, the judging module is also used for:

[0029] If at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of operation of the replacement transformer, and if reducing the load of the replacement transformer still cannot make both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of operation after replacing the transformer, then the operation mode of the medium-voltage side bus is adjusted for optimization, and the simulation model is simulated and analyzed again after optimization.

[0030] Further, the equivalent parameters of the healthy phase transformer include: the equivalent resistance per unit value of the healthy phase transformer, the equivalent reactance per unit value of the healthy phase transformer, the equivalent conductance per unit value of the healthy phase transformer, and the equivalent susceptance per unit value of the healthy phase transformer;

[0031] The equivalent parameters of the replacement phase transformer include: the equivalent resistance per unit value of the replacement phase transformer, the equivalent reactance per unit value of the replacement phase transformer, the equivalent conductance per unit value of the replacement phase transformer, and the equivalent susceptance per unit value of the replacement phase transformer.

[0032] Furthermore, the steady-state characteristic indicators include: transmission power on three sides of the main transformer, three-phase current imbalance, three-phase voltage imbalance, zero-sequence current, zero-sequence voltage and parallel operation capability of the main transformer;

[0033] The transient characteristic indicators include: maximum short-circuit current and magnetizing inrush current of the no-load transformer when the switch is closed.

[0034] Furthermore, the judging module is also used for:

[0035] The load capacity of the replaced main transformer is checked to obtain the boundary load rate of the replaced three-phase main transformer.

[0036] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0037] The present invention provides a 500kV single-phase autotransformer replacement operation evaluation method and system, wherein the method comprises: obtaining the nameplate parameters of a healthy phase transformer and the nameplate parameters of a replacement phase transformer, and respectively calculating the equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer according to the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer; obtaining the system equivalent parameters and load parameters under the peak load condition, the valley load condition and the daily operation load condition of the target substation; establishing a simulation model according to the operation mode of the target substation, inputting the calculated equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer into the simulation model, and adjusting the medium voltage side gear voltage of the replacement phase transformer ratio parameter to be consistent with the medium voltage side gear voltage of the healthy phase transformer ratio parameter, and if there is no consistent gear, taking the voltage closest to the gear; calculating the system equivalent parameters under the peak load condition, the valley load condition and the daily operation load condition of the target substation; and load parameters are input into the simulation model; the simulation model is simulated and analyzed to obtain the operating data of the peak load condition, the operating data of the valley load condition, and the operating data of the daily operation load condition; the steady-state characteristic index and the transient characteristic index are calculated according to the operating data of the peak load condition, the operating data of the valley load condition, and the operating data of the daily operation load condition; it is determined whether the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation; if the steady-state characteristic index and the transient characteristic index both meet the conditions for the feasibility of the replacement transformer operation, it is feasible from the operation technical point of view, and the replacement operation can be implemented after the economic feasibility and the engineering installation feasibility are evaluated by the operation department; if at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of the replacement transformer operation, the load of the replacement transformer is reduced until the steady-state characteristic index and the transient characteristic index both meet the conditions for the feasibility of the replacement transformer operation. The main transformer replacement object of the present invention is a 500kV single-phase autotransformer. The asymmetry problem caused by its replacement of the main transformer is more serious than the problem of replacing the double-winding three-phase transformer in the existing research. The present invention standardizes the modeling and evaluation of the collection demand to fill the gap in the system analysis method of this sector; the present invention quantifies the factors that have a direct impact on the asymmetry, such as the short-circuit voltage percentage, transformer capacity, winding equivalent capacitance, voltage tap, etc., to form an equivalent mathematical model of the transformer. On the one hand, it can form a universal model for the joint action of multiple factors, and on the other hand, it can simplify the modeling simulation analysis; the present invention proposes a comprehensive evaluation method for comprehensive three-phase voltage imbalance, zero-sequence current, interphase circulating current, operation thermal stability and other indicators, which can realize the evaluation of load capacity and operation stability. At the same time, the evaluation and analysis can provide a reference for the load limit after replacement, protection setting verification, and supporting secondary equipment configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 It is a flow chart of a 500kV single-phase autotransformer replacement operation evaluation method provided by a certain embodiment of the present invention;

[0040] Figure 2 It is a device diagram of a 500kV single-phase autotransformer replacement operation evaluation system provided by a certain embodiment of the present invention;

[0041] Figure 3 It is a structural diagram of an electronic device provided by a certain embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0044] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0045] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0046] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0047] The first aspect.

[0048] See also Figure 1 The present invention provides a 500kV single-phase autotransformer replacement operation evaluation method, comprising:

[0049] S100, obtaining nameplate parameters of a healthy phase transformer and nameplate parameters of a replacement phase transformer, and respectively calculating equivalent parameters of the healthy phase transformer and equivalent parameters of the replacement phase transformer according to the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer.

[0050] S200, obtaining system equivalent parameters and load parameters under peak load conditions, valley load conditions, and daily operation load conditions of the target substation.

[0051] S300. Establish a simulation model according to the operation mode of the target substation, input the calculated equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer into the simulation model, and adjust the medium-voltage side gear voltage of the replacement phase transformer ratio parameters to be consistent with the medium-voltage side gear voltage of the healthy phase transformer ratio parameters. If there is no consistent gear, take the gear closest to the voltage.

[0052] S400, inputting the system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation into the simulation model.

[0053] S500, performing simulation analysis on the simulation model to obtain operation data of a peak load condition, operation data of a valley load condition, and operation data of a daily operation load condition.

[0054] S600. Calculate steady-state characteristic indexes and transient characteristic indexes according to the operating data of the peak load condition, the operating data of the valley load condition, and the operating data of the daily operating load condition.

[0055] S700: Determine whether the steady-state characteristic index and the transient characteristic index meet the condition of replacement transformer operation feasibility.

[0056] S800. If both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of replacement operation, then it is feasible from the operation technology point of view. After the operation department evaluates the economic feasibility and the feasibility of the engineering installation, the replacement operation can be implemented.

[0057] S900. If at least one of the steady-state characteristic index and the transient characteristic index does not satisfy the condition for the feasibility of the replacement transformer operation, reduce the load of the replacement transformer until both the steady-state characteristic index and the transient characteristic index satisfy the condition for the feasibility of the replacement transformer operation.

[0058] In a specific implementation of the embodiments of the present invention, if at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of the operation of the replacement transformer, if reducing the load of the replacement transformer still cannot make both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the operation after replacing the transformer, the operation mode of the medium-voltage side bus is adjusted for optimization, and the simulation model is simulated and analyzed again after the optimization.

[0059] Preferably, the equivalent parameters of the healthy phase transformer include: the equivalent resistance per unit value of the healthy phase transformer, the equivalent reactance per unit value of the healthy phase transformer, the equivalent conductance per unit value of the healthy phase transformer and the equivalent susceptance per unit value of the healthy phase transformer;

[0060] The equivalent parameters of the replacement phase transformer include: the equivalent resistance per unit value of the replacement phase transformer, the equivalent reactance per unit value of the replacement phase transformer, the equivalent conductance per unit value of the replacement phase transformer, and the equivalent susceptance per unit value of the replacement phase transformer.

[0061] Preferably, the steady-state characteristic indicators include: transmission power on three sides of the main transformer, three-phase current imbalance, three-phase voltage imbalance, zero-sequence current, zero-sequence voltage and parallel operation capability of the main transformer;

[0062] The transient characteristic indicators include: maximum short-circuit current and magnetizing inrush current of the no-load transformer when the switch is closed.

[0063] In another specific implementation of the embodiment of the present invention, if at least one of the steady-state characteristic index and the transient characteristic index does not satisfy the condition of the feasibility of the replacement operation, it also includes:

[0064] The load capacity of the replaced main transformer is checked to obtain the boundary load rate of the replaced three-phase main transformer.

[0065] The method provided by the present invention comprehensively considers the transformer equivalent mathematical model under the combined effects of factors such as short-circuit voltage percentage, transformer capacity, winding equivalent capacitance, voltage taps, etc. before and after transformer replacement, thereby simplifying the parameter input of modeling analysis and improving the efficiency of modeling simulation; on this basis, a comprehensive evaluation is carried out with three-phase voltage unbalance, zero-sequence current, interphase circulating current, operating thermal stability, etc. as indicators, and a universal 500kV single-phase autotransformer replacement operation evaluation method and measures to optimize operating capacity are proposed.

[0066] In another specific embodiment of the present invention, the present invention provides a 500kV single-phase autotransformer replacement operation evaluation method, comprising:

[0067] S1: Standardized collection information. The collection parameters include the following: (1) Nameplates of 500 kV healthy phase transformer and replacement phase transformer, including rated capacity SN1 / S N2 / S N3 (S N1 =S N2 =S N ), rated voltage U N1 / U N2 / U N3 , no-load loss P0, short-circuit voltage percentage U k(1-2) / U k(1-3) / U k(2-3) (%), short circuit loss P k(1-2) / P k(1-3) / P k(2-3) ; (2) Dielectric loss test data of the original transformer and the replacement transformer (including the measured values ​​of the transformer winding-to-winding and winding-to-ground capacitance); (3) Routine operation of the substation, operating voltages of the high, medium and low voltage sides before and after replacement; (4) Substation load conditions, peak load, valley load and daily operating load during replacement operation; (5) Substation protection configuration, existing protection settings; (6) Reactive power compensation configuration and detailed parameters on the low voltage side of the substation; (7) Substation power consumption and parameters; (8) Equivalent parameters of the high voltage side system of the substation under different load conditions.

[0068] S2: Calculate the equivalent parameters of the operating transformer (healthy phase) (all converted to the high voltage side):

[0069] (1) Calculate the equivalent resistance per unit value of the transformer:

[0070]

[0071] In the formula, R * T1 , R * T2 , R * T3 P is the per unit resistance of the transformer at the high, medium and low voltage sides; k(1-2) , P k(1-3) , P k(2-3) The short-circuit losses of the high-medium, high-low, and medium-low windings on the transformer nameplate;

[0072] (2) Calculate the equivalent reactance per unit value of the transformer:

[0073]

[0074] Where, X * T1 , X * T2 , X * T3 U is the per unit value of the equivalent reactance on the high, medium and low voltage sides of the transformer; k(1-2)(%), U k(1-3) (%), U k(2-3) (%) is the percentage of short-circuit voltage of high-middle, high-low and medium-low windings on the transformer nameplate;

[0075] (3) Calculate the equivalent per unit conductance value of the transformer:

[0076]

[0077] In the formula, G * T is the per unit value of the transformer equivalent conductance; P0 is the no-load loss in the transformer nameplate; U N is the rated voltage of the high voltage side of the transformer; S N is the rated capacity of the transformer;

[0078] (4) Calculate the transformer equivalent susceptance standard value:

[0079]

[0080] In the formula, B * T is the transformer equivalent susceptance, I0 is the no-load current; U N , S N The meaning is the same as in (3).

[0081] S3: Calculate the equivalent parameters of the operating transformer (replacement phase) (all converted to the high voltage side), the calculation method is the same as S2.

[0082] S4: Build a model on the PSCAD / EMTDC platform according to the target substation operation mode, and fill in the corresponding parameters obtained in steps S1-S3 according to the PSCAD model requirements.

[0083] S5: Unify the tap position on the medium voltage side of the transformer and adjust the medium voltage side voltage of the replacement phase transformer ratio parameter in the PSCAD model to be consistent with the healthy phase.

[0084] S6: Modify the load parameters and simulate the peak load, valley load and daily operation load conditions respectively. Export the result data of PSCAD simulation analysis of peak load, valley load and daily operation load conditions: (1) active / reactive power and three-phase current / voltage, line current / voltage on the high, medium and low voltage sides; (2) positive, negative and zero sequence current / voltage on the high, medium and low voltage sides decomposed by PSCAD online fast Fourier transform module; (3) circulating current between healthy phase and replacement phase.

[0085] S7: Calculate indicators based on the data obtained in S6, mainly including steady-state characteristic indicators (S8-S11) and transient characteristic indicators (S12-S13).

[0086] S8: Indicator 1: Transmission power on three sides of the main transformer.

[0087] Main transformer high voltage side transmission power P Hx , Q Hx ; Medium voltage side transmission power P Mx , Q Mx ; Low voltage side transmission power P Lx , Q Lx ; x = 1, 2, 3 represent phases A, B, and C respectively. The transmission power on the three sides of the main transformer should meet the main transformer capacity requirements.

[0088] S9: Indicator 2: three-phase imbalance ε.

[0089] (1) Three-phase current imbalance

[0090] (2) Three-phase voltage imbalance

[0091] In the formula, U1 and U2 are the positive and negative sequence effective values ​​of voltage; I1 and I2 are the positive and negative sequence effective values ​​of current. According to the national standard, the normal voltage imbalance degree of the common connection point of the power system is generally ε U ≤2%, short-term ε U ≤4%; Each user connected to the public connection point causes the normal voltage imbalance at this point to be generally ε U ≤1.3%.

[0092] S10: Index: 3: Zero sequence current I0, zero sequence voltage U0

[0093] The zero-sequence current and voltage should meet the operating requirements of relevant protection and supporting equipment, should not cause false operation or refusal to operate of relevant protection of the target station, and should not exceed the operating limit of supporting equipment.

[0094] S11: Indicator 4: Main transformer parallel operation capability.

[0095] When two sets of main transformers are operated in parallel with three phases (i.e. 220kV combined operation), the parallel operation capacity needs to be verified. According to the national standard, the transformer parallel operation must meet the requirements that the difference in the transformation ratio of each transformer does not exceed ±5%, the difference in impedance voltage does not exceed ±10%, the connection groups are exactly the same, and the capacity ratio must be less than 3:1.

[0096] S12: Indicator 5: Maximum short-circuit current.

[0097] The short-circuit current is affected by the short-circuit impedance. The change of the short-circuit impedance will cause the short-circuit current of the phase to increase or decrease. The maximum short-circuit current of the phase is I km , then I km The short-circuit current limit of the main transformer and related equipment should not be exceeded.

[0098] S13: Indicator 6: Excitation inrush current of no-load transformer when the circuit is closed.

[0099] The excitation inrush current is an important factor affecting transformer performance and system stability. By replacing the high-voltage side switch of the transformer with no-load at different times within half a cycle, the maximum excitation inrush current on the high-voltage side Do not exceed the standard requirements and the limits of main transformers and related equipment.

[0100] S14: If all indicators of S8-S13 meet the corresponding requirements under peak load, valley load and daily operating load conditions, it can be considered that the replacement transformer is feasible from the operational technical point of view. The evaluation indicators provide a basis for judgment for the protection department and supporting equipment. After the operation department evaluates the economic feasibility and the feasibility of the project installation, the replacement operation can be implemented.

[0101] S15: If some indicators of the simulation results under the above load conditions cannot meet the corresponding requirements, it is necessary to verify the load capacity of the replaced main transformer according to the method of S16 to obtain the maximum load capacity of the replaced main transformer, that is, the boundary load rate.

[0102] S16: Starting with the load that does not meet the index requirements, gradually reduce the load carried by the replacement transformer in the model until all indicators meet the corresponding requirements. The ratio of the load size to the rated capacity of the transformer at this time is the boundary load rate.

[0103] S17: If the boundary load rate adjusted by S16 cannot meet the operation requirements, the operation mode of the medium voltage busbar can be adjusted for optimization. In the case of parallel operation, the voltage imbalance is better; in the case of separate operation, the current imbalance is better. Adjust the operation mode and repeat S5-S16 steps to conduct evaluation.

[0104] S18: The obtained boundary load rate and corresponding evaluation index results provide a reference for operating load limitation, protection setting, and related equipment configuration.

[0105] The beneficial effects of the method provided by the embodiment of the present invention include:

[0106] (1) The main transformer to be replaced is a 500kV single-phase autotransformer. The asymmetry problem caused by replacing the main transformer is more serious than the problem of replacing a double-winding three-phase transformer in existing research. The standardized modeling and evaluation of the capital collection demand in this invention fills the gap in the system analysis method of this sector;

[0107] (2) The present invention quantifies factors that have a direct impact on asymmetry, such as short-circuit voltage percentage, transformer capacity, winding equivalent capacitance, and voltage tap, to form a transformer equivalent mathematical model. On the one hand, it can form a universal model for the joint action of multiple factors, and on the other hand, it can simplify modeling and simulation analysis.

[0108] (3) The present invention proposes a comprehensive evaluation method that integrates indicators such as three-phase voltage unbalance, zero-sequence current, interphase circulating current, and operating thermal stability, which can realize the evaluation of load capacity and operating stability. At the same time, the evaluation and analysis can provide a reference for load limitation after replacement, protection setting verification, and supporting secondary equipment configuration.

[0109] The second aspect.

[0110] See also Figure 2 An embodiment of the present invention provides a 500kV single-phase autotransformer replacement operation evaluation system, comprising:

[0111] The data acquisition and calculation module 10 is used to obtain the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer, and calculate the equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer according to the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer respectively; the data acquisition and calculation module 10 is also used to obtain the system equivalent parameters and load parameters under the peak load condition, the valley load condition and the daily operation load condition of the target substation.

[0112] The simulation module 20 is used to establish a simulation model according to the operating mode of the target substation, input the calculated equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer into the simulation model, and adjust the medium-voltage side gear voltage of the replacement phase transformer ratio parameter to be consistent with the medium-voltage side gear voltage of the healthy phase transformer ratio parameter. If there is no consistent gear, the voltage closest to the gear is taken; the simulation module 20 is also used to input the system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation into the simulation model.

[0113] The operating condition data calculation module 30 is used to perform simulation analysis on the simulation model to obtain the operating data of the peak load condition, the operating data of the valley load condition, and the operating data of the daily operating load condition.

[0114] The characteristic index calculation module 40 is used to calculate the steady-state characteristic index and the transient characteristic index according to the operation data of the peak load condition, the operation data of the valley load condition, and the operation data of the daily operation load condition.

[0115] The judgment module 50 is used to judge whether the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation; if the steady-state characteristic index and the transient characteristic index both meet the conditions for the feasibility of the replacement transformer operation, it is feasible from the operation technical point of view, and after the economic feasibility and engineering installation feasibility are evaluated by the operation department, the replacement operation can be implemented; if at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of the replacement transformer operation, the load of the replacement transformer is reduced until the steady-state characteristic index and the transient characteristic index both meet the conditions for the feasibility of the replacement transformer operation.

[0116] In a specific implementation of the embodiment of the present invention, the judgment module 50 is further used to:

[0117] If at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of operation of the replacement transformer, and if reducing the load of the replacement transformer still cannot make both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of operation after replacing the transformer, then the operation mode of the medium-voltage side bus is adjusted for optimization, and the simulation model is simulated and analyzed again after optimization.

[0118] Preferably, the equivalent parameters of the healthy phase transformer include: the equivalent resistance per unit value of the healthy phase transformer, the equivalent reactance per unit value of the healthy phase transformer, the equivalent conductance per unit value of the healthy phase transformer and the equivalent susceptance per unit value of the healthy phase transformer;

[0119] The equivalent parameters of the replacement phase transformer include: the equivalent resistance per unit value of the replacement phase transformer, the equivalent reactance per unit value of the replacement phase transformer, the equivalent conductance per unit value of the replacement phase transformer, and the equivalent susceptance per unit value of the replacement phase transformer.

[0120] Preferably, the steady-state characteristic indicators include: transmission power on three sides of the main transformer, three-phase current imbalance, three-phase voltage imbalance, zero-sequence current, zero-sequence voltage and parallel operation capability of the main transformer;

[0121] The transient characteristic indicators include: maximum short-circuit current and magnetizing inrush current of the no-load transformer when the switch is closed.

[0122] In another specific implementation of the embodiment of the present invention, the judging module 50 is further configured to:

[0123] The load capacity of the replaced main transformer is checked to obtain the boundary load rate of the replaced three-phase main transformer.

[0124] The system provided by the present invention comprehensively considers the transformer equivalent mathematical model under the combined effects of factors such as short-circuit voltage percentage, transformer capacity, winding equivalent capacitance, voltage taps, etc. before and after transformer replacement, thereby simplifying the parameter input of modeling analysis and improving the efficiency of modeling simulation; on this basis, a comprehensive evaluation is carried out with three-phase voltage unbalance, zero-sequence current, interphase circulating current, operating thermal stability, etc. as indicators, and a universal 500kV single-phase autotransformer replacement operation evaluation method and measures to optimize operating capacity are proposed.

[0125] The third aspect.

[0126] The present invention provides an electronic device, the electronic device comprising:

[0127] processor, memory, and bus;

[0128] The bus is used to connect the processor and the memory;

[0129] The memory is used to store operation instructions;

[0130] The processor is used to call the operation instruction, and the executable instruction enables the processor to perform operations corresponding to a 500kV single-phase autotransformer replacement operation evaluation method as shown in the first aspect of the present application.

[0131] In an alternative embodiment, an electronic device is provided, such as Figure 3 As shown, Figure 3 The electronic device 5000 shown includes: a processor 5001 and a memory 5003. The processor 5001 and the memory 5003 are connected, such as through a bus 5002. Optionally, the electronic device 5000 may also include a transceiver 5004. It should be noted that in actual applications, the transceiver 5004 is not limited to one, and the structure of the electronic device 5000 does not constitute a limitation on the embodiments of the present application.

[0132] Processor 5001 may be a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. Processor 5001 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0133] The bus 5002 may include a path to transmit information between the above components. The bus 5002 may be a PCI bus or an EISA bus, etc. The bus 5002 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0134] The memory 5003 may be a ROM or other type of static storage device that can store static information and instructions, a RAM or other type of dynamic storage device that can store information and instructions, or an EEPROM, a CD-ROM or other optical disk storage, an optical disk storage (including a compressed optical disk, a laser disk, an optical disk, a digital versatile disk, a Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.

[0135] The memory 5003 is used to store application code for executing the solution of the present application, and the execution is controlled by the processor 5001. The processor 5001 is used to execute the application code stored in the memory 5003 to implement the content shown in any of the above method embodiments.

[0136] Among them, electronic devices include but are not limited to: mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc.

[0137] The fourth aspect.

[0138] The present invention provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the method for evaluating the replacement operation of a 500kV single-phase autotransformer as shown in the first aspect of the present application is implemented.

[0139] Another embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer-readable storage medium is run on a computer, the computer can execute the corresponding content in the aforementioned method embodiment.

Claims

1. A 500kV single-phase autotransformer replacement operation evaluation method, characterized in that: include: Obtaining nameplate parameters of a healthy phase transformer and nameplate parameters of a replacement phase transformer, and respectively calculating equivalent parameters of the healthy phase transformer and equivalent parameters of the replacement phase transformer according to the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer; Obtain system equivalent parameters and load parameters under peak load conditions, valley load conditions, and daily operation load conditions of the target substation; A simulation model is established according to the operation mode of the target substation, the calculated equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer are input into the simulation model, and the medium voltage side gear voltage of the replacement phase transformer ratio parameter is adjusted to be consistent with the medium voltage side gear voltage of the healthy phase transformer ratio parameter; Inputting system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation into the simulation model; Performing simulation analysis on the simulation model to obtain operation data of peak load conditions, operation data of valley load conditions, and operation data of daily operation load conditions; Calculate steady-state characteristic index and transient characteristic index according to the operation data of the peak load condition, the operation data of the valley load condition, and the operation data of the daily operation load condition; Determine whether the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of replacing the transformer operation; If both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation, the replacement transformer operation is feasible from the perspective of operation technology. After the economic feasibility and engineering installation feasibility are evaluated by the operation department, the replacement transformer operation is implemented; If at least one of the steady-state characteristic index and the transient characteristic index does not satisfy the condition for the feasibility of the replacement transformer operation, the load of the replacement transformer is reduced until both the steady-state characteristic index and the transient characteristic index satisfy the condition for the feasibility of the replacement transformer operation.

2. A 500kV single-phase autotransformer replacement operation evaluation method as claimed in claim 1, characterized in that: If at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of the replacement transformer operation, and if reducing the load of the replacement transformer still cannot make both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation, the operation mode of the medium-voltage side bus is adjusted for optimization, and the simulation model is simulated and analyzed again after optimization.

3. A 500kV single-phase autotransformer replacement operation evaluation method as claimed in claim 1, characterized in that: The equivalent parameters of the healthy phase transformer include: the equivalent resistance per unit value of the healthy phase transformer, the equivalent reactance per unit value of the healthy phase transformer, the equivalent conductance per unit value of the healthy phase transformer, and the equivalent susceptance per unit value of the healthy phase transformer; The equivalent parameters of the replacement phase transformer include: the equivalent resistance per unit value of the replacement phase transformer, the equivalent reactance per unit value of the replacement phase transformer, the equivalent conductance per unit value of the replacement phase transformer, and the equivalent susceptance per unit value of the replacement phase transformer.

4. A 500kV single-phase autotransformer replacement operation evaluation method as claimed in claim 1, characterized in that: The steady-state characteristic indicators include: transmission power on three sides of the main transformer, three-phase current imbalance, three-phase voltage imbalance, zero-sequence current, zero-sequence voltage and parallel operation capability of the main transformer; The transient characteristic indicators include: maximum short-circuit current and magnetizing inrush current of the no-load transformer when the switch is closed.

5. A 500kV single-phase autotransformer replacement operation evaluation method as claimed in claim 1, characterized in that: If at least one of the steady-state characteristic index and the transient characteristic index does not meet the condition of the feasibility of the replacement transformer operation, the method further includes: The load capacity of the replaced main transformer is checked to obtain the boundary load rate of the replaced three-phase main transformer.

6. A 500kV single-phase autotransformer replacement operation evaluation system, characterized in that: include: A data acquisition calculation module is used to obtain the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer, and calculate the equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer according to the nameplate parameters of the healthy phase transformer and the nameplate parameters of the replacement phase transformer; the data acquisition calculation module is also used to obtain the system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation; A simulation module is used to establish a simulation model according to the operation mode of the target substation, input the calculated equivalent parameters of the healthy phase transformer and the equivalent parameters of the replacement phase transformer into the simulation model, and adjust the medium voltage side gear voltage of the replacement phase transformer ratio parameter to be consistent with the medium voltage side gear voltage of the healthy phase transformer ratio parameter; the simulation module is also used to input the system equivalent parameters and load parameters under the peak load condition, the valley load condition, and the daily operation load condition of the target substation into the simulation model; A working condition data calculation module is used to perform simulation analysis on the simulation model to obtain operating data of peak load working conditions, operating data of valley load working conditions, and operating data of daily operating load working conditions; A characteristic index calculation module, used to calculate a steady-state characteristic index and a transient characteristic index according to the operation data of the peak load condition, the operation data of the valley load condition, and the operation data of the daily operation load condition; The judgment module is used to judge whether the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation; if both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation, it is feasible from the operation technical point of view, and after the economic feasibility and engineering installation feasibility are evaluated by the operation department, the replacement transformer operation is implemented; if at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of the replacement transformer operation, the load of the replacement transformer is reduced until both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation.

7. A 500kV single-phase autotransformer replacement operation evaluation system as claimed in claim 6, characterized in that: The judging module is further used for: If at least one of the steady-state characteristic index and the transient characteristic index does not meet the conditions for the feasibility of the replacement transformer operation, and if reducing the load of the replacement transformer still cannot make both the steady-state characteristic index and the transient characteristic index meet the conditions for the feasibility of the replacement transformer operation, then the operation mode of the medium-voltage side bus is adjusted for optimization, and the simulation model is simulated and analyzed again after optimization.

8. A 500kV single-phase autotransformer replacement operation evaluation system as claimed in claim 6, characterized in that: The equivalent parameters of the healthy phase transformer include: the equivalent resistance per unit value of the healthy phase transformer, the equivalent reactance per unit value of the healthy phase transformer, the equivalent conductance per unit value of the healthy phase transformer, and the equivalent susceptance per unit value of the healthy phase transformer; The equivalent parameters of the replacement phase transformer include: the equivalent resistance per unit value of the replacement phase transformer, the equivalent reactance per unit value of the replacement phase transformer, the equivalent conductance per unit value of the replacement phase transformer, and the equivalent susceptance per unit value of the replacement phase transformer.

9. A 500kV single-phase autotransformer replacement operation evaluation system as claimed in claim 6, characterized in that: The steady-state characteristic indicators include: transmission power on three sides of the main transformer, three-phase current imbalance, three-phase voltage imbalance, zero-sequence current, zero-sequence voltage and parallel operation capability of the main transformer; The transient characteristic indicators include: maximum short-circuit current and magnetizing inrush current of the no-load transformer when the switch is closed.

10. A 500kV single-phase autotransformer replacement operation evaluation system as claimed in claim 6, characterized in that: The judging module is further used for: The load capacity of the replaced main transformer is checked to obtain the boundary load rate of the replaced three-phase main transformer.

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